Abstract: The present disclosure relates to a chemically treated zinc-based plated steel sheet that is superior in weather resistance, water resistance, blackening resistance and film adhesion. A chemical conversion film having a thickness 0.5-10 ?m is formed by coating and drying a chemical treatment solution on a surface of an aluminum-containing zinc-based alloy plated steel sheet. The chemical treatment solution contains a fluororesin containing 0.05-5% by weight of a hydrophilic functional group selected from the group consisting of a carboxyl group and a sulfonic acid group and 7-20% by weight of a fluorine atom, the fluororesin in which a number-average molecular weight is 1,000-2,000,000, and an oxoate, a fluoride, a hydroxide, an organic salt, a carbonate or a peroxygenated salt of a group 4A metal.

Abstract: Disclosed is a chemical conversion coated Al-plated steel sheet which has excellent weather resistance, water resistance and coating film adhesion. Specifically, a chemical conversion coating liquid is applied over and dried on the surface of an Al alloy-plated steel sheet, thereby forming a chemical conversion coating film that has a film thickness of 0.5-10 ?m. The chemical conversion coating liquid contains: a fluorine-containing olefin resin, which contains 7-20% by mass of F atoms and 0.05-5% by mass of hydrophilic functional groups that are selected from among a carboxyl group, a sulfonic acid group and salts of carboxyl group and sulfonic acid group and has a number average molecular weight within the range of 1,000-2,000,000; and an oxygen acid salt, fluoride, hydroxide, organic acid salt, carbonate or peroxygenated salt of a group 4A metal.

Abstract: A new processed steel sheet comprising of a steel base coated with a Zn or its alloy plating layer and a converted layer, which contains both of at least an insoluble or scarcely-soluble metal compound and at least a soluble metal compound. The insoluble or scarcely-soluble compound may be one or more of valve metal oxides or hydroxides, and the soluble compound may be one or more of valve metal fluorides. The converted layer may be also composed of one or more of complex compounds of Mn and Ti. The insoluble or scarcely-soluble compound acts as a barrier for insulation of a steel base from an atmosphere, while the soluble compound exhibits a self-repairing faculty to repair defective parts of the converted layer. Due to the converted layer, the processed steel sheet is remarkably improved in corrosion resistance, without the presence of chromium compounds which would put harmful influences on the environment.

Abstract: A separator for a low-temperature fuel cell comprises a stainless steel substrate S having a surface to which carbonaceous particles such as graphite particles GP or carbon black aggregates CA adhere with dotted distribution. The carbonaceous particles are preferably bonded through a diffusion layer DL to the surface of the substrate S. The carbonaceous particle-dispersed layer may be a plating layer in which graphite particles GP or carbon black aggregates CA are dispersed or formed by thermal decomposition of organic components in a carbonaceous particle-dispersed paint applied to the surface of the substrate S. Since carbonaceous particles free from oxide films adhere to the surface of the acid-resistant stainless steel substrate S, contact resistance of the separator is sufficiently low. Consequently, a power generator having a plurality of fuel cells laminated together exhibits high power-generating efficiency with less heat loss caused by a Joule heat.

Abstract: A new processed steel sheet comprises a steel base coated with a Zn or its alloy plating layer and a converted layer, which contains both of at least an insoluble or scarcely-soluble metal compound and at least a soluble metal compound. The insoluble or scarcely-soluble compound may be one ore more of valve metal oxides or hydroxides, and the soluble compound may be one or more of valve metal fluorides. The converted layer may be also composed of one ore more of complex compounds of Mn and Ti. The insoluble or scarcely-soluble compound acts as a barrier for insulation of a steel base from an atmosphere, while the soluble compound exhibits a self-repairing faculty to repair defective parts of the converted layer. Due to the converted layer, the processed steel sheet is remarkably improved in corrosion resistance, without presence of chromium compounds which would put harmful influences on the environment.

Abstract: A Zn-Mg binary coating layer formed on a steel sheet has the tri-layered structure that the first sublayer composed of a Zn-Mg alloy having Mg concentration of 0.5 wt. % or less, the second sublayer composed of a Zn-Mg alloy having Mg concentration of 7 wt. % or more and the third sublayer composed of a Zn-Mg alloy having Mg concentration of 0.5 wt. % or less are successively laminated. The coating layer may have the penta-layered structure wherein sublayers composed of a Zn-Mg alloy having Mg concentration of 2-7 wt. % are additionally interposed between the high-Mg and low-Mg sublayers. A Zn-Fe or Zn-Fe-Mg alloy layer may be formed at the boundary between the substrate steel and the coating layer. The adhesion ratio of the first sublayer to the top sublayer is preferably 1.2 or more, while the high-Mg sublayer is preferably conditioned to the mixed structure of a Zn.sub.2 Mg phase with a Mg-dissolved Zn phase.

Abstract: A Zn--Mg binary coating layer formed on a steel sheet has the tri-layered structure that the first sublayer composed of a Zn--Mg alloy having Mg concentration of 0.5 wt. % or less, the second sublayer composed of a Zn--Mg alloy having Mg concentration of 7 wt. % or more and the third sublayer composed of a Zn--Mg alloy having Mg concentration of 0.5 wt. % or less are successively laminated. The coating layer may have the penta-layered structure wherein sublayers composed of a Zn--Mg alloy having Mg concentration of 2-7 wt. % are additionally interposed between the high-Mg and low-Mg sublayers. A Zn--Fe or Zn--Fe--Mg alloy layer may be formed at the boundary between the substrate steel and the coating layer. The adhesion ratio of the first sublayer to the top sublayer is preferably 1.2 or more, while the high-Mg sublayer is preferably conditioned to the mixed structure of a Zn.sub.2 Mg phase with a Mg-dissolved Zn phase.

Abstract: An iron-based heat-generating material excellent in oxidation resistance at an elevated temperature which comprises an iron-based alloy capable of generating heat by passing electricity therethrough and a coating of aluminum and oxygen formed on the surface of the alloy, the amount of the oxygen in the coating is less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. The material can be prepared by vacuum evaporation of Al onto the surface of the iron-based alloy wherein an oxygen partial pressure in a vacuum gaseous atmosphere for the vacuum evaporation is adjusted so that there is formed on the surface of the alloy a coating consisting of aluminum and oxygen, the amount of the oxygen in the coating being less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. When the material is heated in ambient or oxidizing atmosphere, an outermost layer of the coating is rapidly converted to Al.sub.2 O.sub.3.

Abstract: An iron-based heat-generating material excellent in oxidation resistance at an elevated temperature which comprises an iron-based alloy capable of generating heat by passing electricity therethrough and a coating of aluminum and oxygen formed on the surface of the alloy, the amount of the oxygen in the coating is less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. The material can be prepared by vacuum evaporation of Al onto the surface of the iron-based alloy wherein an oxygen partial pressure in a vacuum gaseous atmosphere for the vacuum evaporation is adjusted so that there is formed on the surface of the alloy a coating consisting of aluminum and oxygen, the amount of the oxygen in the coating being less than the stoichiometric amount of oxygen in Al.sub.2 O.sub.3. When the material is heated in ambient or oxidizing atmosphere, an outermost layer of the coating is rapidly converted to Al.sub.2 O.sub.3.